Potassium hydride

Potassium hydride, KH, is the inorganic compound of potassium and hydride. It is a white solid, although commercial samples appear gray. A powerful base that is useful in organic synthesis, it is also a dangerously reactive compound. For this reason it is sold commercially as a slurry (~35%) in mineral oil or sometimes paraffin wax to facilitate dispensing.

Preparation

Potassium hydride is produced by direct combination of the metal and hydrogen:

This reaction was discovered by Humphry Davy soon after his 1807 discovery of potassium, when he noted that the metal would vaporize in a current of hydrogen when heated just below its boiling point.

Potassium hydride is soluble in fused hydroxides (such as molten sodium hydroxide) and salt mixtures, but not in organic solvents.

Reactions

KH reacts with water according to the reaction:

Potassium hydride is a superbase that is stronger than sodium hydride. It is used to deprotonate certain carbonyl compounds and amines to give, respectively, enolates and amides.